Replace other types of beverages with water!
If you know that you are also drinking other types of beverages over the course of the day, you can use that as a trick to introduce more water to your diet. Tea is a great way to up your water intake as long as you do not add any sweeteners to it so that one is not one that you should swap out for water.
If you know you drink soft drinks over the day or that you enjoy a cold glass of soda more often than not, then you should look into replacing them with water. That way, you will also lose the added sugar intake, which can be horrible for your health.
If you are used to drinking these types of sugary beverages, then you should start slowly. Instead of having a can of Coke with your dinner, swap it out for water. When you go out, instead of getting a soft drink, choose to get water instead. Same if you end up stopping at a fast food joint: getting those huge cokes is not good for your health, and if you got water instead, you would be racing your daily water intake goal faster!
A benefit of this swap, besides drinking more water, is that you will also be losing weight since you are no longer getting too much sugar in your system!